Brill, the publishing house, have released a free font, which is great for New Testament studies. It contains 5,100 characters, including comprehensive Greek, a fair amount of Cyrillic and Arabic, the basic characters of a dozen or so other languages (from Telegu to Hebrew), and several Christian or other religious symbols.
The only problem (and it's a big problem), is that Windows does a pretty bad job of rendering it on screen. It prints fine (and looks fine on screen in an application that fully supports Open Type), but looks pretty awful on everything else. I presume Macs won't have the problem.
http://www.brill.nl/news/brill-typeface